The Gardin Ultima that I've seen have been mid to late 1980s, sport models, positioned around the crossover between entry level and mid-range. The geometry fell between racing and touring.
One possibility for the large gap between the tyre and seat tube would be pushing the wheel to the back of the dropout slots. However, it looks like there would be a clearance issue at the brake bridge if it the wheel was pulled much farther forward and that clearance issue doesn't appear to be attributable to overly fat tyres being installed.
The gap actually reminds me of what was typical with many of the frames desiged for 650C wheelsets. The chainstays couldn't be shortened very much, due to the possibility of heel strike on the rear derailleur. However, these bicycles also give the appearance of a abnormally high BB (due to the lower wheel axles), which the subject bicycle does not appear to have. Regardless, I'm attaching a photo of a Nishiki Beta NFS with 650C wheels, that exhibits a similar size gap.
It's hard to identify the actual reason for the large gap, given the single and poor photo. Things might become readily evident with more and better photos.
